Microelectromechanical Systems (“MEMS”) devices are employed as actuators and sensors in a wide variety of applications. Capacitive-sensing MEMS devices, for example, are now commonly employed in many different electronic devices to sense acceleration, vibration, device orientation, and other inertia-related parameters. Such MEMS devices function by sensing changes in capacitance between electrodes in a transducer structure. The transducer structure may include, for example, a number of stationary electrodes or “fingers” interposed with and spaced apart from a number of movable electrodes or “fingers” in a comb-type arrangement. The movable electrodes are rigidly joined to a larger movable structure commonly referred to as a “proof mass,” which is resiliently suspended over an underlying substrate. During operation of the MEMS device in an example, a voltage differential is applied across the stationary or movable electrodes. As the proof structure moves in response to acceleration of the MEMS device, the movable electrodes are displaced with respect to the fixed electrodes and the capacitances between the electrodes vary accordingly. By monitoring these capacitances, the acceleration or other movement of the MEMS device can be determined.
Interconnect lines route electrical signals from the electrodes of the transducer structure to bond pads or other contacts located on the exterior of the MEMS device. Depending upon the particular manner in which the MEMS device is fabricated, the bond pads may be formed on laterally-projecting ledges of the MEMS device referred to as “bond pad shelves.” Such an arrangement is often employed in implementations wherein the MEMS device includes a cover piece or cap, which sealingly encloses the transducer structure to prevent environmental contamination thereof. In one common package architecture, the bond pads of the MEMS device are electrically connected to a MEMS-monitoring circuit, such as an application specific integrated circuit, packaged with the MEMS device. In implementations wherein the bond pads are formed on bond pad shelves and, therefore, disposed at an elevation between the upper and lower surfaces of the MEMS device, wire bonding is typically required to form the desired electrical connections between MEMS bond pads and the MEMS-monitoring circuit.
For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction and may omit depiction, descriptions, and details of well-known features and techniques to avoid unnecessarily obscuring the exemplary and non-limiting embodiments of the invention described in the subsequent Detailed Description. It should further be understood that features or elements appearing in the accompanying figures are not necessarily drawn to scale unless otherwise stated. For example, the dimensions of certain elements or regions in the figures may be exaggerated relative to other elements or regions to improve understanding of embodiments of the invention.